Initial Technical Brief v0.2

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  • Filename: industrial-cooling-initial-technical-brief.md

  • File Type: md

  • Path: docs/client/industrial-cooling-initial-technical-brief.md

Description

Source client technical brief used for requirements derivation

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Industrial Cooling Systems S.L.

Cabinet Cooling Protection Unit

Initial Technical Brief

Version: 0.2

Document Type: Pre-Requirements Technical Brief

1. Product Overview

Industrial Cooling Systems S.L. is developing a compact cooling protection unit intended for installation inside industrial electrical cabinets.

The unit is responsible for:

  • Monitoring cabinet environmental conditions
  • Controlling a cooling fan
  • Protecting cabinet electronics from overheating
  • Signaling abnormal operating conditions

The product will operate continuously in industrial environments and must prioritize reliability and protective behavior.

2. Intended Operation

The system shall:

  • Continuously monitor internal cabinet temperature
  • Monitor cooling fan rotational speed (RPM feedback)
  • Monitor supply voltage
  • Control fan activation
  • Provide alarm signaling under abnormal conditions

The device must prioritize equipment protection over continued operation.

In unsafe conditions, protective behavior must override normal cooling logic.

3. Safety Expectations (Fixed Thresholds)

The following safety limits are fixed and shall not be configurable.

3.1 Critical Overtemperature

If internal temperature exceeds 85°C, the system must:

  • Disable active outputs
  • Activate alarm signaling
  • Enter protective behavior

3.2 Voltage Protection

If supply voltage is:

  • Below 18V, or
  • Above 30V,

The system must enter protective behavior.

3.3 Fan Failure Detection

If the cooling fan is commanded ON and no valid RPM feedback is detected within a defined timeout period, the system must treat this as a fault.

The timeout value may be configurable within defined limits.

4. Configurable Parameters

The following parameters shall be configurable:

  • Fan activation temperature (default 60°C)
  • Fan deactivation temperature (default 50°C)
  • Warning temperature threshold (default 70°C)
  • Fan failure detection timeout (default 5 seconds)

Configuration values must:

  • Be validated before use
  • Stay within predefined safe ranges
  • Never override fixed safety limits

5. Diagnostics & Logging

The device shall:

  • Store the last detected fault condition
  • Provide structured fault identifiers
  • Maintain firmware version information
  • Allow inspection of current operating status

Persistent fault memory is desirable but not mandatory in the initial version.

6. Reliability Expectations

The firmware must:

  • Operate deterministically
  • Avoid undefined behavior
  • Handle invalid sensor readings gracefully
  • Prevent unstable output oscillations
  • Recover safely from transient conditions

7. Interfaces

7.1 Communication Interface

The device shall provide an industrial communication interface for:

  • Reading current measurements
  • Reading current status
  • Reading last fault information
  • Writing configuration parameters

Preferred interface:

  • RS-485 using Modbus RTU protocol

7.2 Local Indication

The device shall include:

  • One RGB status LED

The LED shall indicate:

  • Normal operation
  • Warning condition
  • Fault or protective behavior

Exact LED behavior (steady or blinking patterns) will be defined during firmware design.